1. Field of the Invention
The present invention relates to a lighting device having a light source module with a plurality of light sources bonded thereon and a plurality of light spreading plates secured onto the substrate through stick objects and hollow caps.
2. Descriptions of the Related Art
The conventional direct-lit backlight module used for a display comprises LEDs directly disposed under the display panel. To enhance the uniformity, a diffuser or a scattering film being disposed in front of the LEDs is needed. Although the direct-lit backlight module is suitable for the large-scale displays, it can be well imagined that the direct-lit backlight module is not only too complicated to arrange the light sources onto the bezel but also too thick since a certain distance is needed for the diffuser or the scattering film to be disposed above the light sources in order to obtain an uniform light output over a large area. In other words, the direct-lit backlight module faces a dilemma to provide a uniform brightness or a thinner configuration.
In order to provide a lighting device being slim and providing uniform backlight, a light spreading plate has been developed. The details of the light spreading plate are described in U.S. patent application Ser. No. 12/879,173 filed on Sep. 10, 2010. U.S. Ser. No. 12/879,173 discloses a plurality of light spreading plates being fixed onto a source module by using adhesive. However, at least two disadvantages of fixing the light spreading plates to the source module by the adhesive are occurred: (1) intensive labor to glue each light spreading plate onto the source module is required, and (2) the adhesion may be deteriorated especially within the environment of high temperature and high humidity.
Moreover, if a diffuser plate is disposed above the light spreading plate, spacers disposed between the light spreading plate and the diffuser plate are needed. Thus, the spacers being glued onto the surface of the light spreading plate may be not reliable enough and thus the intensive labor is also required.
Given the above, a novel and slim lighting device which can be manufactured in a more efficient and reliable manner to provide a uniform backlight is needed in this field.